Re: [PATCH 2/2] commands: test: add based support for bash-test style

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 04.07.23 00:58, Marco Felsch wrote:
> Add [[ expression ]] support which allow pattern matching like:
> 
>   - [[ "foo1" == "foo*" ]]
>   - [[ "foo" != "bar" ]]
> 
> Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> ---
>  commands/Kconfig | 13 +++++++++++++
>  commands/test.c  | 39 ++++++++++++++++++++++++++++++++++-----
>  2 files changed, 47 insertions(+), 5 deletions(-)
> 
> diff --git a/commands/Kconfig b/commands/Kconfig
> index 4d3ff631a8..615e96aa9d 100644
> --- a/commands/Kconfig
> +++ b/commands/Kconfig
> @@ -1219,6 +1219,19 @@ config CMD_TEST
>  		  !, =, !=, -eq, -ne, -ge, -gt, -le, -lt, -o, -a, -z, -n, -d, -e,
>  		  -f, -L; see 'man test' on your PC for more information.
>  
> +if CMD_TEST
> +
> +config CMD_TEST_BASH_COMP
> +	tristate
> +	select CONFIG_FNMATCH

select FNMATCH, no CONFIG_
Does this really need its own symbol? Can't you just use CONFIG_GLOB
and amend the help text?

> +	prompt "test bash-compatibility"
> +	help
> +	  Enable minimal support for bash compatible tests: [[ ]] to allow
> +	  pattern matching via: == and !=
> +
> +# end CMD_TEST
> +endif
> +
>  config CMD_TRUE
>  	tristate
>  	default y
> diff --git a/commands/test.c b/commands/test.c
> index c1b84c42ef..77e15aeb03 100644
> --- a/commands/test.c
> +++ b/commands/test.c
> @@ -11,9 +11,13 @@
>  #include <command.h>
>  #include <fs.h>
>  #include <linux/stat.h>
> +#ifdef CONFIG_CMD_TEST_BASH_COMP
> +#include <fnmatch.h>
> +#endif
>  
>  typedef enum {
>  	OPT_EQUAL,
> +	OPT_EQUAL_BASH,
>  	OPT_NOT_EQUAL,
>  	OPT_ARITH_EQUAL,
>  	OPT_ARITH_NOT_EQUAL,
> @@ -36,6 +40,7 @@ typedef enum {
>  
>  static char *test_options[] = {
>  	[OPT_EQUAL]			= "=",
> +	[OPT_EQUAL_BASH]		= "==",
>  	[OPT_NOT_EQUAL]			= "!=",
>  	[OPT_ARITH_EQUAL]		= "-eq",
>  	[OPT_ARITH_NOT_EQUAL]		= "-ne",
> @@ -67,18 +72,37 @@ static int parse_opt(const char *opt)
>  	return -1;
>  }
>  
> +static int string_comp(const char *left_op, const char *right_op, bool bash_test)
> +{
> +#ifdef CONFIG_CMD_TEST_BASH_COMP
> +	if (bash_test)
> +		return fnmatch(right_op, left_op, 0);
> +#endif

Scripts that execute differently depending on a barebox config option
is not good user experience. I think it would be better if [[ is an
error if support is missing.

Also can't the #ifdef be replaced with a IS_ENABLED()

> +	return strcmp(left_op, right_op);
> +}
> +
>  static int do_test(int argc, char *argv[])
>  {
>  	char **ap;
>  	int left, adv, expr, last_expr, neg, last_cmp, opt, zero;
>  	ulong a, b;
>  	struct stat statbuf;
> +	bool bash_test = false;
>  
>  	if (*argv[0] == '[') {
>  		argc--;
> -		if (*argv[argc] != ']') {
> -			printf("[: missing `]'\n");
> -			return 1;
> +		if (!strncmp(argv[0], "[[", 2)) {

This is equivalent to argv[0][1] == '['

> +			if (strncmp(argv[argc], "]]", 2) != 0) {
> +				printf("[[: missing `]]'\n");
> +				return 1;
> +			}
> +			if (IS_ENABLED(CONFIG_CMD_TEST_BASH_COMP))
> +				bash_test = true;
> +		} else {
> +			if (*argv[argc] != ']') {
> +				printf("[: missing `]'\n");
> +				return 1;
> +			}
>  		}
>  	}
>  
> @@ -183,10 +207,11 @@ static int do_test(int argc, char *argv[])
>  			b = simple_strtol(ap[2], NULL, 0);
>  			switch (parse_opt(ap[1])) {
>  			case OPT_EQUAL:
> -				expr = strcmp(ap[0], ap[2]) == 0;
> +			case OPT_EQUAL_BASH:
> +				expr = string_comp(ap[0], ap[2], bash_test) == 0;
>  				break;
>  			case OPT_NOT_EQUAL:
> -				expr = strcmp(ap[0], ap[2]) != 0;
> +				expr = string_comp(ap[0], ap[2], bash_test) != 0;
>  				break;
>  			case OPT_ARITH_EQUAL:
>  				expr = a == b;
> @@ -233,7 +258,11 @@ static int do_test(int argc, char *argv[])
>  	return expr;
>  }
>  
> +#ifdef CONFIG_CMD_TEST_BASH_COMP
> +static const char * const test_aliases[] = { "[", "[[", NULL};
> +#else
>  static const char * const test_aliases[] = { "[", NULL};
> +#endif
>  
>  BAREBOX_CMD_HELP_START(test)
>  BAREBOX_CMD_HELP_TEXT("Options:")

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